OIl Rig Design and Inspections

Design of Oil Drilling and Service Structures to American Petroleum Institute (API) 4F

Inspections and Recertifications to CAODC Requirements

An oil rig in the parlance of the industry is a oil derrick and associated equipment needed to drill for oil and gas.

The main components needed are a drilling mast usually about 120 feet tall capable of supporting up to around 1,000,000 pounds,

A drawworks capable of pulling up to about 100,000 pounds (using multi-sheave block and tackle), traveling block, swivel and kelly, kelly bushing and rotary table plus machinery to turn the drawworks and rotary table. These are built onto a platform usually 20-30 feet above the ground. Located under the platform is a well head consisting of a blow out preventer stack and diverter.

To the side of the derrick are horizontal pipe racks and on one side of the derrick itself is a place to store pipe as it in run in and out of the hole. A wire rope drum is there also to be able to replace worn drawworks cable.

There are power make-up tongs (a power pipe wrench) and pipe clamp available on the rig floor, plus a dog house and instruments.

Off to the side are a number of metal tanks and usually some earthen pits dug on site. And a set of two or more triple acting reciprocating slush pumps for circulating drilling mud to the traveling block and through the drill pipe and drill bit. Usually because of the remote locations there are diesel generators and tanks to furnish all motive power and lights.

Located above the tanks are mud treatment equipment to remove cuttings, mix mud, and de-gas the return mud. These are usually aftermarket equipment.

Also associated with a rig are a number of trailers and a well pad which are aftermarket furnished (not part of the purchased rig). The trailers are the offices and accommodations for the HMFWIC (that's short for the company man) and various service personnel who monitor instruments and check and take care of the drilling mud.

That is the composition of a drilling rig. The rigs are usually able to be broken down into modular parts that fit on flat bed trucks for transport to and from drilling sites where they may be for a couple of weeks to a year or more. Usually the manufacturer assembles a new rig for acceptance tests and then disassembles and ships the parts. Thereafter the rig is broken down and moved from site to site as needed.

Expendables - pipe, fuel, mud, water and chemicals and drill bits are arranged by the rig operator as needed.